Hantaviruses predominantly infect endothelial cells (ECs), and in the absence of cell lysis, cause diseases associated with dramatic increases in vascular permeability. Andes virus (ANDV) infection results in acute pulmonary edema and respiratory insufficiency termed hantavirus pulmonary syndrome (HPS). Vast pulmonary capillary beds provide an abundance of ECs for ANDV to infect and infection of ECs provides a primary means for ANDV to increase capillary permeability and cause edema. ANDV infection dramatically enhances EC permeability in response to VEGF and this is not observed following infection by non-pathogenic TULV or in response to TNF1. Our recent findings indicate that ANDV infection of ECs results in the hyperphosphorylation of VEGFR2, increased dissociation of VE-cadherin from AJs and increased paracellular permeability. We have also shown that ANDV induced permeability is inhibited by angiopoietin-1 (Ang-1), or sphingosine-1 phosphate (S1P) which antagonize VEGF directed permeability. These findings suggest that ANDV induced edema may be blocked by inhibiting VEGFR2 signaling pathways. ANDV infection of Syrian hamsters is the only animal model of hantavirus disease which closely mimics HPS, resulting in fatal acute pulmonary edema. This model permits the study of potential therapeutic compounds against ANDV disease and was developed by Jay Hooper the co- investigator on this proposal. In this joint proposal with Jay Hooper, we propose to apply our basic understanding of ANDV induced EC permeability to the Syrian Hamster model of hantavirus disease. Here we will evaluate the efficacy of compounds that enhance EC barrier functions for their ability to prevent HPS-like disease in Syrian hamsters.